Hi Marcelo
Are these security TRs? If yes then you can ask your security team to attach the roles in 3-4 transport request instead of one. A normal TR with 500 roles takes about 1-2 hrs to release.
If not from security then check the number of ABAP object in the TRs. Also check if the temp file is full.
/usr/sap/trans/tmp
Also follow the following SCN link